Resilient hinging device for chairs and the like

ABSTRACT

In a resilient hinge for chairs and the like, having an upper hinge part to be attached to the seat or back of the chair and pivoted on a bottom hinge part to be fixed to the bottom frame, with a biased spring member acting therebetween for resiliently opposing backward tilting, the spring member is capable of being displaced radially to the pivotal axis for adjusting the biasing torque, the spring member engaging an entraining slide guided in the fixed hinge part. Movement of the entraining slide is caused by operating a handle on a lever pivoted on an upwardly projecting cone on the fixed hinge part and having teeth engaging a rack guided in the fixed hinge part for motion parallel to the hinge axis and carrying studs engaging oblique slots in the entraining member so as to afford a force-increasing transmission of motion from the lever to the spring member. The handle extends substantially to the edge of the seat so as to be easily accessible. The cone is hollow for matching a column in the bottom frame of the chair. The spring member is composed of leaf springs bent into U-shape opening towards the rear and placed one outside the other. They are in mutual contact at the bend and at the ends of the respective inner springs, with the lengths of the springs increasing from the innermost to the outermost. The lower legs of the leaf springs are bifurcated with diverging inner edges and straddle the cone, and the upper legs have a substantially complementary taper.

United States Patent 91 Werner June 26, 1973 RESILIENT HINGING DEVICEFOR CHAIRS AND THE LIKE [76] Inventor: Per Gunnar Werner, 1460 Spro,

Norway [22] Filed: Apr. 6, 1971 21 Appl. No.: 131,781

Primary Examiner-Francis K. Zugel Assistant ExaminerPeter A.Aschenbrenner Att0rney-Holman & Stern ABSTRACT In a resilient hinge forchairs and the like, having an upper hinge part to be attached to theseat or back of the chair and pivoted on a bottom hinge part to be fixedto the bottom frame, with a biased spring member acting therebetween forresiliently opposing backward tilting, the spring member is capable ofbeing displaced radially to the pivotal axis for adjusting the biasingtorque, the spring member engaging an entraining slide guided in thefixed hinge part. Movement of the entraining slide is caused byoperating a handle on a lever pivoted on an upwardly projecting cone onthe fixed hinge part and having teeth engaging a rack guided in thefixed hinge part for motion parallel to the hinge axis and carryingstuds engaging oblique slots in the entraining member so as to afford aforce-increasing transmission of motion from the lever to the springmember. The handle extends substantially to the edge of the seat so asto be easily accessible. The cone is hollow for matching a column in thebottom frame of the chair. The spring member is composed of leaf springsbent into U-shape opening towards the rear and placed one outside theother. They are in mutual contact at the bend and at the ends of therespective inner springs, with the lengths of the springs increasingfrom the innermost to the outermost. The lower legs of the leaf springsare bifurcated with diverging inner edges and straddle the cone, and theupper legs have a substantially complementary taper.

14 Claims, 7 Drawing Figures I/ "I 4111 J Y/ x \16 7 f2 1111PATENTEDJUNZSISH SHEET 2 BF 3 BACKGROUND OF THE INVENTION DESCRIPTION OFTHE PREFERRED EMBODIMENT The invention will be described more in detailin con- The invention relates to resilient hinging devices for actionwith a Preferred embodiment illustrated in the chairs and the likecomprising a member adapted to be attached to the seat or back of achair and mounted for pivotal movement about a horizontal axis of amember adapted to be attached to the bottom frame of the chair, againstthe action of a spring member acting between these hinge memberssubstantially tangentially to the pivotal axis and biased in a positionof the movable hinge member defined by abutments, and in which positionthe spring member can be displaced by an actuating member in a directionsubstantially radial to the pivotal axis and transversely of its actingdirection, for adjusting the biasing torque. A pivotal hinge of thiskind is previously known, for example from the applicants U. S. Pat. No.3,284,133 dated Nov. 8, 1966 and has the considerable advantage that anadjustment of the baising torque and hence of the relation between thespring torque and pivotal angle can take place without substantiallyvarying the spring tension or overcoming spring force.

SUMMARY OF THE INVENTION The present invention has for an object toimprove pivotal hinges of the kind referred to, primarily by making itpossible to effect the adjustment easily while sitting in the chair. Inprior structure described in the said patent this is hardly possiblesince the adjustment is effected with a screw spindle which is placed ina position difficult to access on the bottom side of the chair and whichin the case of a considerable biasing force, which is desirable foraffording a sufficient torque in a device of small dimensions, must beturned with a considerable force in order to overcome the friction onthe loaded spring member.

An improvement afforded by the present invention in this connectionconsists in that the actuating member instead comprises a lever which ismounted on one of the hinge members for pivotal motion in asubstantially horizontal plane and is connected by a force-increasingmechanism to an entraining member mechanically connected to the springmember and mounted for displacement in the direction of adjustment. Thelever may be provided with a handle extending substantially to the edgeof the seat of the chair so that the manipulation can take place easilywith a long moment arm and the mechanism will nevertheless largelyremain concealed, as the lever with the handle may extend closely underthe seat and the shape of the handle can be adapted to the shape anddimensions of the seat without changing the remaining mechanism.

The invention also teaches further features which make the manner ofoperation consistent with a compact design and easy mounting, andfurther provides a spring member which is adapted to be used in thisconnection and at the same time is designed for affording the desiredresilient action while using a minimum of material and for being madefrom commercially available spring steel stock.

accompanying drawings.

in the drawings the FIGS. 1 to 4 are in half the scale of the remainingFIGS. 5 to 7.

FIG. 1 is an exploded side view of the mechanism partly in section inthe central vertical plane.

FIG. 2 is a bottom view of the actuating lever with handle.

FIG. 3 is a top view of the spring member partly in section in thecentral horizontal plane indicated at III- III in FIG. 6.

FIG. 4 is a bottom view of a sliding rack.

FIG. 5 shows the pivotal hinge as viewed from the front and in sectionthrough the pivotal axis as indicated by the line VV in FIG. 6.

FIG. 6 is a side view of the same in longitudinal section substantiallyalong the line VI-VI in FIG. 7, yet without the spring member beingshown in section.

FIG. 7 is a top view of the bottom part of the hinge with the adjustingmechanism inserted.

The device comprises a metallic bottom part or fixed hinge member 1largely of the shape of a box open at the top and at the rear. From adownwardly offset portion 2 of the box bottom there projects upwards anupwardly tapering open hollow cone 3 adapted to be mounted on a column 4or the like in the bottom frame of the chair (diagrammatically indicatedin FIG. 6). In the side walls 5, 5 there are mounted bearing sleeves 6,6 for pivotally supporting a transverse hollow shaft 7 which at itsextremities outside the bottom part is fixed in downwardly projectingside walls 8 of an upper part or movable hinge member 9 formed with alargely rectangular top plate 10, which for example by means of screwsin the comers can be attached to the part 11' to be supported, such as achair seat, a supporting frame for a chair back or the like.

Slidably supported on the bottom of the fixed member 1 is an entrainingslide 12 guided between the walls 5, the slide 12 extending throughoutthe width of the bottom in front of the cone 3 and being formed with twobranches extending on either side of the cone and terminating in upwardprojections 13, 13 formed by bending the end portions upwards andinwards, whereas the branches at 12 rest on the upper face of thebottom, whereas the branches at the rear rest on ribs 14 projecting fromthe portion 2 and extending obliquely to either side.

The slide 12 serves as an entraining member for a spring member 15 ofthe pivotal hinge. As appears from the FIGS. 1, 3, 5 and 6, this memberis composed of a plurality, four in the example shown, of leaf springsextending outside each other and bent into U-shape opening towards therear and having one leg above and one below the shaft 7. In order tomake the stress on the spring material as even as possible at allpoints, the dimensions of the various springs are adapted to the loadpartly by staggering the length of the leaf springs so that it decreasesfrom the outermost to the innermost and partly by making the effectivewidth of each spring decrease towards the free extremities both in theupper leg and in the lower leg. The radii of curvature in the bend arestaggered so that each spring when engaging the bend of the adjacentspring surrounding it exerts an outward pressure on the same at theextremities of its legs. The upward branches taper towards the end andthe outermost slidably engages a plane bottom or sliding face 16 on theupper part 9. The lower legs are cut out deeply and symmetrically fromthe end and project on either side of the cone 3, the outermost leghaving U-shaped end portions engaging the projections 13 of the slide12. The free edges of the upper and lower legs may conveniently havesubstantially complementary shapes, so that the leaf springs can bestamped practically without loss.

In the slide 12 there are formed two oblique parallel slots 17, 17 intowhich project studs 18 of correspondingly oblique parallelogram shapefrom a sliding rack 19 supported in the bottom of the member 1 fordisplacement parallel to the shaft 7 just in front of the cone 3. On itsbottom side the rack 19 is formed with teeth 20 engaging a correspondingtoothed wheel segment 21 on a lever 22 pivotally mounted with a circularopening 23 on the root of the cone 3 and substantially concentric to thelatter. The lever 22 rests on the bottom of the lowered portion 2 at adistance below the slide 12 and is capable of pivotal movement in thehorizontal plane by a suitable angle limited by the ribs 14 formingstops for the lever. The lever 22 projects behind the bottom part 1 andextends further at an obtuse angle towards the right hand side of thehinge. To the free extremity of the lever there is attached a handle 24of suitable design and length for easy operation by the person sittingin the chair. For arresting the lever in the desired angular position,the lowered bottom portion 2 is, near its rear edge, formed withteeth-25 in its upper face, which are engaged by a tooth 26 (FIG. 2) onthe bottom side of the lever 22, which is keptdepressed by a leaf spring26' (partly broken away in FIG. 7) supported in grooves 26 in the ribs14 and locked against upward movement by engaging the lower ends of ribs28 on the inner faces of the side walls 5.

Another possibility of arresting the lever 22 in desired angularpositions might be to make the slope of the slots 17 in the entrainingslide 12 so small that the sliding connection with the studs 18 will beselfarresting.

In the starting position shown, the spring member 15 is biased, thelower legs thereof exerting downward pressure on the projections 13 ofthe slide 12 and hence via the latter on the ribs 14 in the bottom ofthe fixed member 1, whereas the upper legs act on the sliding face 16 ofthe movable member 9 and hence exert a torque on the same in theclockwise direction whereby the top plate of the movable member ispressed against abutments 30, 30 at the upper edges of the forwardportions of the side walls of the fixed member at the front. When theseated person then leans backwards, it

vwill be possible for the movablehinge member while increasing the loadon the spring member to turn counter-clockwise as viewed in FIG. 6 untilits top plate engages abutments 31, 31 on the side walls 5 at the rear.If the person then desires to change the biasing torque, it will bepossible in the starting position of the mechanism shown, in whichposition the sliding face 16 extends largely parallel to the guidingdirection for the entraining slide 12, to turn the lever22 in onedirection or the other, whereby the lever via the segment 21 and theteeth will displace the rack 19, which will then by the stud and slotconnections 17, 18 cause a displacement of the slide 12 and hence of thespring memher 15 forwards or backwards. Hence, the line of action of theresulting spring force will be displaced towards the pivotal axisdefined by the shaft 7 so that the spring member will act with anincreased or reduced moment arm and its torque will varycorrespondingly.

The mounting is extremely simple. At first the lever 22, the retainingspring 26', the sliding rack 19, the entraining slide 12 and the springmember 15 are simply placed in position in the bottom part 1, in whichthe sleeves 6 have been mounted, and in a suitable jig the whole iscompressed together with the upper part 9 until the axial bores of thelatter become aligned with the bearing sleeves, whereafter the shaft 7is forced into position and riveted.

What I claim is 1. Resilient hinging device for chairs and the like,comprising a first hinge member for attachment to a seat or back of thechair, a second hinge member for attachment to a bottom frame of thechair, abutments on said second hinge member, said first hinge memberbeing supported for pivotal movement about a horizontal axis on saidsecond hinge member, a spring member acting between said first andsecond hinge members substantially tangentially to the pivotal axis andbiased in a starting position of the first hinge member defined by theabutments, in which position the spring member can be displaced by anactuating member in a direction substantially radial to the pivotal axisand transversely of its acting direction for adjusting the biasingtorque, characterized in that the actuating member comprises a leversupported on one of said hinge members for pivotal motion in asubstantially horizontal plane, a force increasing mechanism, anentraining member mechanically connected to the spring member andsupported for displacement in the direction of adjustment and said leverbeing connected via the force increasing mechanism to the entrainingmember.

2. Resilient hinging device as claimed in claim 1, characterized in thatthe lever is, at its inner extremity, in entraining engagement with aslide guided in the direction of the hinge axis and engaging theentraining member for the spring member by a double stud and slotconnection.

3. Resilient hinging device as claimed in claim 2, characterized in thatthe stud and slot connections are self-arresting.

4. Resilient hinging device as claimed in claim 2, characterized in thatthe lever is formed with a toothed wheel segment and the transverselymovable slide with corresponding rack teeth.

5. Resilient hinging device as claimed in claim 1, characterized in thatthe entraining member is guided in the second hinge member and transmitspressure between the latter and the spring member.

6. Resilient hinging device as claimed in claim 1, in

which the second hinge member is provided with a hollow cone formounting on a column in the bottom frame of the chair, characterized inthat the hollow cone projects upwards towards the first hinge member. 7.Resilient hinging device as claimed in claim 6, characterized in thatthe lever is mounted in the second hinge member on the outside of thehollow cone and with its pivotal axis substantially in the axis of thecone. 8. Resilient hinging device as claimed in claim 7, characterizedin that the portion of the spring member acting on the second hingemember is distributed substantially symmetrically on both sides of thecone.

9. Resilient hinging device as claimed in claim 1, characterized in thatthe spring member is composed of a plurality of leaf springs curved inthe plane normal to the hinge axis and placed in mutual engagement oneoutside the other, the outermost leaf spring engaging the hinge membersat its ends.

10. Resilient hinging device as claimed in claim 9, characterized inthat the leaf springs have decreasing length and radii of curvaturecounted from the outermost to the innermost, the individual springsengaging the respective adjacent springs on the outside at their endsand at the bottom of the bends.

11. Resilient hinging device as claimed in claim 9, characterized inthat the springs are bent slightly more than 180 and loosely insertedone into the other.

12. Resilient hinging device as claimed in claim 9,

characterized in that the effective width of each spring decreasestowards both ends thereof.

13. Resilient hinging device as claimed in claim 12, characterized inthat the end portions of each spring have mutually complementary shapes.

14. Resilient hinging device as claimed in claim 6, characterized inthat the spring member is composed of a plurality of leaf springs curvedin the plane normal to the pivotal axis and placed in mutual engagementone outside the other, the outermost leaf spring engaging the hingemembers at its ends, that the end portions of the springs at the endengaging the second hinge member are bifurcated with diverging inneredges and straddle said cone, and that their end portions at theopposite end have a substantially complementary taper.

1. Resilient hinging device for chairs and the like, comprising a firsthinge member for attachment to a seat or back of the chair, a secondhinge member for attachment to a bottom frame of the chair, abutments onsaid second hinge member, said first hinge member being supported forpivotal movement about a horizontal axis on said second hinge member, aspring member acting between said first and second hinge memberssubstantially tangentially to the pivotal axis and biased in a startingposition of the first hinge member defined by the abutments, in whichposition the spring member can be displaced by an actuating member in adirection substantially radial to the pivotal axis and transversely ofits acting direction for adjusting the biasing torque, characterized inthat the actuating member comprises a lever supported on one of saidhinge members for pivotal motion in a substantially horizontal plane, aforce increasing mechanism, an entraining member mechanically connectedto the spring member and supported for displacement in the direction ofadjustment and said lever being connected via the force increasingmechanism to the entraining member.
 2. Resilient hinging device asclaimed in claim 1, characterized in that the lever is, at its innerextremity, in entraining engagement with a slide guided in the directionof the hinge axis and engaging the entraining member for the springmember by a double stud and slot connection.
 3. Resilient hinging deviceas claimed in claim 2, characterized in that the stud and slotconnections are self-arresting.
 4. Resilient hinging device as claimedin claim 2, characterized in that the lever is formed with a toothedwheel segment and the transversely movable slide with corresponding rackteeth.
 5. Resilient hinging device as claimed in claim 1, characterizedin that the entraining member is guided in the second hinge member andtransmits pressure between the latter and the spring member. 6.Resilient hinging device as claimed in claim 1, in which the secondhinge member is provided with a hollow cone for mounting on a column inthe bottom frame of the chair, characterized in that the hollow coneprojects upwards towards the first hinge member.
 7. Resilient hingingdevice as claimed in claim 6, characterized in that the lever is mountedin the second hinge member on the outside of the hollow cone and withits pivotal axis substantially in the axis of the cone.
 8. Resilienthinging device as claimed in claim 7, characterized in that the portionof the spring member acting on the second hinge member is distributedsubstantially symmetrically on both sides of the cone.
 9. Resilienthinging device as claimed in claim 1, characterized in that the springmember is composed of a plurality of leaf springs curved in the planenormal to the hinge axis and placed in mutual engagement one outside theother, the outermost leaf spring engaging the hinge members at its ends.10. Resilient hinging device as claimed in claim 9, characterized inthat the leaf springs have decreasing length and radii of curvaturecounted from the outermost to the innermost, the individual springsengaging the respective adjacent springs on the outside at their endsand at tHe bottom of the bends.
 11. Resilient hinging device as claimedin claim 9, characterized in that the springs are bent slightly morethan 180* and loosely inserted one into the other.
 12. Resilient hingingdevice as claimed in claim 9, characterized in that the effective widthof each spring decreases towards both ends thereof.
 13. Resilienthinging device as claimed in claim 12, characterized in that the endportions of each spring have mutually complementary shapes. 14.Resilient hinging device as claimed in claim 6, characterized in thatthe spring member is composed of a plurality of leaf springs curved inthe plane normal to the pivotal axis and placed in mutual engagement oneoutside the other, the outermost leaf spring engaging the hinge membersat its ends, that the end portions of the springs at the end engagingthe second hinge member are bifurcated with diverging inner edges andstraddle said cone, and that their end portions at the opposite end havea substantially complementary taper.